Effects of ovariectomy, gonadal steroid replacement and photoperiod on plasma beta-endorphin in the ewe.

The effects of gonadectomy, photoperiod and ovarian steroid replacement on plasma beta-endorphin concentrations were studied in 2 experiments using mature ewes. In Experiment 1 ovariectomy resulted in an increased plasma beta-endorphin concentration. Changing the photoperiod from long to short daylength had little effect on beta-endorphin, but transfer from short to long photoperiod caused a fall in the beta-endorphin level. In Experiment 2 ovariectomy again caused an increase in plasma beta-endorphin. Treatment with progesterone, estradiol or a combination of both failed to reduce the level to preovariectomy values, although LH concentrations were reduced. No diurnal rhythmicity in beta-endorphin secretion was observed.

Oestrus detection in dairy cows by milk temperature measurement.

The milk and body temperatures of 15 cows were monitored twice daily at milking times, over a total of 30 oestrous periods. The best determination of oestrus was based on a temperature rise of at least 0.2 degree C over the corresponding mean temperature of the three preceding days. This resulted in 72 +/- 16 per cent of oestruses, predicted by serial progesterone assays, being successfully detected by serial progesterone assays, being successfully detected and 11 +/- 3 per cent of false positives. The variable extent of the temperature rise at oestrus and the large daily fluctuations in temperature for individual cows, resulted in a moderate oestrus detection rate accompanied by an unacceptable level of false positives.

Time in lairage needed by pigs to recover from the stress of transport.

Two experiments were carried out in which a total of 602 pigs were slaughtered after being held in lairage for periods ranging from less than one hour to 21 hours. In the first experiment the pigs were handled under ideal conditions and slaughtered at the University of Bristol slaughterhouse; in the second the pigs were killed at a commercial plant. Blood samples collected at exsanguination were analysed for indices of stress. There were no consistent effects of time in lairage on the levels of lactate and creatine phosphokinase. Plasma cortisol and beta-endorphin levels were reduced by lairage for three hours or more in the first experiment and cortisol was reduced by lairage for two hours or more in the second; beta-endorphin was not measured in the second experiment. A period of rest in lairage allowed the pigs to recover from transport and the associated handling and the recovery appeared to be complete within two to three hours.

An evaluation of milk temperature measurement for detecting oestrus in dairy cattle. I. Factors affecting measurement of milk temperature.

The paper reports the development of an electronic system of milk temperature measurement and the results of investigations into the influence of milk yield, milk flow and ambient temperature on milk temperature. The milk and body temperatures of randomly selected multiparous Friesian cows were recorded at afternoon milkings. Temperature was measured by bead thermistors housed in perspex probes from which a digital read-out with an accuracy of +/- 0.1 degree C was obtained. Milk temperature was measured at four sites: the short milk tube (SMT), claw piece (CT), and the beginning (BLT) and end of the long milk tube (ELT) with readings being taken every 30 s from the commencement of milking. Body temperature measured with a probe in the vagina (VT) 38.85 +/- 0.02 degrees C) was significantly higher than milk temperature at any of the four sites although a significant positive correlation existed between milk and body temperature. Milk temperature measured at each site decreased with distance from the cows (SMT: 38.64 +/- 0.03 degrees C, ELT: 37.92 +/- 0.04 degrees C). The difference between body and milk temperature was greatest in cows in which milk flow rates were below average (less than 1.37 kg/min) and/or milk yields were below average (less than 7.82 kg/milking). Milk temperature sites SMT and CT were least affected by variation in milk yield or flow, and showed the closest relationship between maximum milk temperature and body temperature. Milk temperature measurement was most reliable when taken during the full flow of milk.

An evaluation of milk temperature measurement for detecting oestrus in dairy cattle. II. Variations in body and milk temperature associated with oestrus.

Vaginal and milk temperatures were measured at each milking in 15 post-partum Friesian cows showing recurrent oestrous cycles for a total of 33 oestruses. A significant increase (P less than 0.001) in both vaginal and milk temperature of 0.29 +/- 0.05 degrees C was shown between the milking prior to oestrus and the milking when oestrus occurred. Cows were divided into 3 groups: showing either a definite temperature rise (27% of cases), a limited temperature rise (60%) or no temperature change (13%) associated with oestrus. Various methods of analysis were investigated to determine the usefulness of the milk temperature data for oestrus prediction. The optimum compromise of high oestrus detection rate (73.3 +/- 16%) and lowest percentage of false positives (10.8 +/- 3.0%) was based on a temperature rise on the day of oestrus of greater than or equal to 0.2 degrees C over the corresponding mean temperature of the preceding three days. These rates suggest the measurement of milk temperature is less useful for oestrus prediction than some earlier reports have indicated.

Plasma beta-endorphin increase following electrical stunning in sheep.

Plasma concentrations of beta-endorphin were assayed in 10 sheep during the conscious state and in relation to electrical stunning. There was a 2 fold increase after stunning, and a further elevation following recovery. On this basis it is possible that recovery from electrical stunning at slaughter may cause undue distress, and it is suggested that exsanguination must be carried out promptly.